102 entries under addition topic. ×

20
add(verb, fix, increase, accept, develop)
16
affix(noun, verb, fix, increase, mark)
16
append(verb, fix, increase, accept, develop)
11
attachment(noun, extra, extension, accessory)
11
extension(noun, part, increase, spread, division)
11
wing(noun, part, increase, delay, development)
9
addendum(noun, increase, delay, development, spread)
9
increase(noun, verb, make, get, advance)
9
supplement(noun, verb, part, advance, increase)
8
adjunct(noun, part, increase, delay, development)
8
ell(noun, division, extra, section)
8
subjoin(verb, fix, increase, secure, join)
7
arm(noun, part, increase, delay, development)
7
tag(verb, fix, mark, join, continue)
6
augmentation(noun, increase, delay, development, spread)
6
block(division, obstruct, anticipate, section)
5
accessory(noun, adjective, part, extra)
5
appendage(noun, part, increase, delay, development)
5
appendix(noun, increase, delay, development, spread)
5
increment(noun, verb, increase, extra, add)
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APASmart Define. (2015). annex thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/annex/thesaurus/synonyms
ChicagoSmart Define. 2015. "annex thesaurus" https://smartdefine.org/annex/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, annex thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/annex/thesaurus/synonyms>.
MLASmart Define. "annex thesaurus" 22 December 2015. Web. 20 September 2026. <https://smartdefine.org/annex/thesaurus/synonyms>